In recent years it has become increasingly important to ensure the integrity of personal barriers, whether these barriers protect against sexually transmitted diseases, the spread of infection during medical procedures, or simply protect the user against contact with relatively innocuous foreign substances.
In manufacturing processes, it is necessary to exercise stringent quality control in order to maintain a quality product. This is particularly important when manufacturing personal barriers which require only a minute flaw in order for the barrier to be defective and fail to achieve its purpose. Additionally, in the case of surgical gloves or contraceptive devices, any flaw in the barrier can lead to a considerable risk.
As surgical operating techniques become more highly developed and more frequently performed, the need for strictly aseptic conditions also increases. Medical personnel depend on surgical or examination gloves to help protect themselves and their patients from the spread of infection, such as hepatitis and AIDS. In order to accomplish this goal and maintain sterility in the medical environment, it is necessary for the gloves to have their structural integrity, i.e. their freedom from punctures, tears, manufacturing imperfections, defects and rips, assured prior to the gloves' sale.
Moreover, sexually transmitted diseases such as herpes and AIDS viruses pose critical health concerns. One of the most common methods to protect against the spread of these infectious diseases is the use of barrier contraceptive devices such as condoms. In order for these barrier contraceptives to be effective against contagious diseases, their structural integrity before use must be assured.
In the past, inflatable products such as gloves or condoms have been tested using a low pressure testing procedure, which included inflating the product and visually inspecting the product for pinholes or other signs of flaws within the surface of the product. The difficulty of this technique, which uses a low inflation pressure of 1-2 lbs per square inch, is that when a product such as a surgical glove is tested, the body of the glove is blown to a large size and the fingers are only slightly inflated, making it difficult to detect flaws in the glove fingers. Indeed, several minutes of the tester's time may be required in observing the fingers of the glove to determine if the product is defective.
Alternatively, a high pressure testing procedure used requires fastening to a circular mandrel the cuff of the glove to be tested. The glove is then inflated with air pressure to a gauge pressure of 1.5 Kpa and the inflated glove is then immersed in water at room temperature to a depth of 200+/-10 mm above the tip of the middle finger. The immersion time is typically on the order of 1.5 minutes. The emergence of air bubbles from the glove is a signal of structural failure in the integrity of the glove.
Latex examination gloves, surgical gloves, and contraceptive devices are conventionally tested for quality pursuant to a number of testing standards developed by the American Society of Testing Materials. Surgical gloves, for example, are tested by distending the glove with 1000 milliliters of water and observing the filled glove at room temperature in a vertical position for a period of time, such as, typically, a minimum of two minutes. The emergence of water from the glove signals a failure in the integrity of the glove. This time consuming test has the additional drawback that it is destructive to the item being tested and therefore cannot be used on 100% of gloves being manufactured but must instead be utilized on only a sample population.
Other methods of testing the structural integrity of elastomeric barriers in the prior art are even more complex. A liquid may be placed inside the barrier and the barrier partially immersed in a second liquid. A current is passed through the liquid inside the barrier, and a detecting means tracks any current increase in the liquid outside the barrier. Such technique is slow and messy and may preclude the use of a lubricant dust on the inside face of the barrier unless the lubricant dust is applied after testing, meaning that testing occurs prior to lubrication thereby reducing the reliability that the quality control testing is designed to induce.
U.S. Pat. No. 5,129,256 discloses a testing method for use in testing condoms for leaks by pressure differential, using a porous mandrel. However, the testing apparatus disclosed in the patent is cumbersome and requires the condom be taken off the mold on which it is formed and placed on the testing apparatus, thus requiring extra handling steps, adding to the danger of jeopardizing the structural integrity of the condom.
Other testing methods used by manufacturers of elastomeric barriers have ranged from batch testing to visual inspection of deflated barriers over a strong light. These techniques do not provide a high degree of accuracy in testing.
The present invention addresses the problems associated with the previous methods for testing the integrity of elastomeric articles. The present invention discloses a highly accurate method wherein the structural integrity of surgical gloves and other elastomeric articles may be tested with a minimum of expense, time, and extra materials. Further, the present invention allows an elastomeric personal barrier to be tested for structural integrity without removing the barrier from the mold on which the barrier was created, thereby reducing the handling of the barrier and the risk that additional handling may threaten the structural integrity of the barrier.
The present invention may also provide a substitute test for the American Society of Testing Materials. In addition, the present invention may obviate the need for air inflation as a current test of structural integrity of elastomeric products. Further, the present invention may provide a structural integrity test used during the manufacturing process and may present a nondestructive testing alternative which may be utilized with 100% of the personal barriers rather than a population sample.